
class Solution {
public:
    double Pow(double x, long long n) {
        if(n==0) return 1.0;
        double tmp=Pow(x,n/2);  
        return (n%2)==0?tmp*tmp:tmp*tmp*x;

    }

    double myPow(double x, int n) {

        return n<0?1.0/Pow(x,-(long long)n):Pow(x,n);

    }
};

